On the same PC there are already installed two OSs: Micorsoft Windows and Debian Etch. I'm installing Lenny on a third partition.
The system can boot from Etch boot CD but not from the Lenny boot CD (showsboot from CD message, then falls back showing grub menu from HD).
On the same PC I can boot the installer in a VirtualBox virtual machine using the same physical drive and physical CD that fails on the real machine.
I think it could be a odd bios issue, I have to mention the motherboard is not completely functional (after an hardware accident it can't see the embedded sata controller any more) but it is working pretty stable after a weekof testing.
I installed successfully Lenny on this PC by running the windows based installer from the same CD.

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